Windows XP and Mac OS X report different amounts of RAM

Discussion in 'Windows, Linux & Others on the Mac' started by medgirl2001, Oct 5, 2009.

  1. medgirl2001 macrumors regular

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    #1
    I was running the Windows 7 upgrade advisor and it gave me a result for RAM that I wasn't expecting. My MacBook Pro has 4 GB of RAM. At least that's what I ordered, and that's what OS X says.

    When I look at the RAM on Windows XP under VMWare Fusion, it tells me I have 512 MB of RAM.

    Where I look at the RAM on Windows XP under BootCamp, it says I have 2.73ish GB of RAM (which doesn't even make sense).

    What is that about?
     
  2. SkyBell macrumors 604

    SkyBell

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    #2
    XP only recognizes 3 GB of RAM max, so it will show up lower.
     
  3. MrCheeto macrumors 68030

    MrCheeto

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    #3
    As for the VMWare Fusion, you have to tell it via the preferences how much ram you want XP to have available to it. So it's not telling you how much ram is in your machine it's telling you how much ram you've given it.

    For bootcamp, I have a feeling XP is only detecting 3 gigs and using 25% of that with your video card (768mb) XP tells you how much ram you have but doesn't include the amount that your video card is using. So if your video card is using 512mb and your machine has 1024mb it will tell you your computer has 512mb of ram available because half of it is being used by the video card.
     
  4. thejadedmonkey macrumors 604

    thejadedmonkey

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    #4
    If you only give VMWare access to 512mb of RAM while you're running it, that's all Windows will be able to see.

    If you run Windows XP in bootcamp, it can only address around 3.3 gigs of RAM, including the video card. Your macbook pro is addressing 512mb of RAM in the video card, leaving 2.7gb left of system RAM to address. If you upgrade to Windows 7 64-bit, you'll see all 4 gigs of RAM.
     
  5. medgirl2001 thread starter macrumors regular

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    #5
    Thanks! That would explain what I saw under BootCamp. Do you know why it would show up so low under VMWare Fusion (only 512 MB)? Is that maybe because of how much RAM is devoted to running OS X simultaneously?

    If I do upgrade to Windows 7 (which I'm debating - not sure yet if I should), will I be able to access more of my RAM?
     
  6. SkyBell macrumors 604

    SkyBell

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    #6
    It depends on how much you allow it in the preferences

    You should be, yes.
     
  7. MrCheeto macrumors 68030

    MrCheeto

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    #7
    If you use a 64-bit operating system it will be able to see all of your ram. Also I've found that windows 7 (the release clients, at least) show you the FULL amount of ram and DON'T subtract the amount being used by your video card :D So 7 should tell you you have 4gb installed!
     
  8. medgirl2001 thread starter macrumors regular

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    #8
    Thanks for all the responses - I think I was posting at the same time as you all were. You answered my last question before I could ask it!

    How much RAM would you recommend letting VMWare Fusion use?

    Also, my video card is the 9400M and the 9600M GT. I thought my card was supposed to have 512 MG of dedicated video memory (in addition to the 4 GB of system RAM). If I have a video card that's supposed to have its own RAM, is XP not able to see that under Boot Camp?
     
  9. MrCheeto macrumors 68030

    MrCheeto

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    #9
    XP will see about 3gb maximum. If you're seeing 2.73gb or whatever it's telling you then that means your card is using .27gb. This should even out to ABOUT 256mb going to your graphics card. I'm not sure how Windows XP handles having 2 cards, though 0.o
     
  10. medgirl2001 thread starter macrumors regular

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    #10
    256 MB would make sense for the card that is shared with system RAM. I guess it's either not seeing the 512 MB card or is seing it as video memory (I'd have to boot back into Windows to see).
     
  11. Stridder44 macrumors 68040

    Stridder44

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    #11
    Good God, there is more misinformation in this thread then I've ever seen in my entire time browsing this forum.

    OP, the reason you only see 512MB under VMWare Fusion is because that's how much you've allowed for it to see/have. You can change this via preferences.

    XP 32-bit (or any 32-bit OS) can view up to 4 GB of RAM, and no more because of a addressing limitation. Any 64-bit version of Windows (Vista, 7) can view up to 16.8 million terabytes of RAM (a theoretical limit, because no one would ever possibly be able to reach it). The reason 32-bit systems with 4 GB of RAM will only show/use a lower number is because the memory address INCLUDES anything your sound card/graphics card/etc. uses, which takes away from that 4 GBs, hence why you'll see 3.8GB or 3.5GB or 3GB (or sometimes even lower) available.

    Some 32-bit systems will say there is 4 GB, but that's all it's doing. You still won't have access to the full 4GB of RAM. It's just like putting a band-aid over the problem. Again, the solution is to move to 64-bit.

    Again, yes, but ONLY if you move to 64-bit. You can't use the "upgrade" option when going from 32-bit to 64-bit, and instead must do a clean install.
     
  12. medgirl2001 thread starter macrumors regular

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    #12
    Thank you for the information. That helps a lot!
     
  13. JessicaD macrumors newbie

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    Jun 3, 2009
    #13
    Medgirl2001,

    How much RAM do you currently have installed? If you are currently using Windows XP 32-bit then the max capacity the operating system will recognize is 3GB. If you plan to migrate over to Windows 7 64-bit then yes you will be able to access more RAM.

    For additional assistance with the migration of Windows XP to Windows 7, Microsoft does have an official Windows 7 Support Forum located here http://tinyurl.com/9fhdl5 . It is supported by product specialists as well as engineers and support teams. You are welcome to check the threads there and receive additional assistance and feedback.

    Jessica
    Microsoft Windows Client Team
     
  14. medgirl2001 thread starter macrumors regular

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    #14
    I have 4 GB of RAM. My XP is 32-bit, as will be my Windows 7 upgrade.

    Thanks for the link!
     
  15. MrQuizK macrumors newbie

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    Aug 28, 2009
    #15
    Oka how about more RAM?

    I currently have 4 GB of RAM in my 17" MacBook Pro with a 3.06 GHz processor. When I use boot camp and check the RAM it shows just a tad lower than 3 GB. When and if I upgrade to Win7, and I buy 4 more gigs of RAM will it show the full 8 gigs of ram? I REALLY NO NOT want to condone Win7 and any windows product but I need it for Adobe Production Premium CS4 (Ran in Boot Camp). I do heavy graphics editing and compositing along with (un)compressed HD video editing. I really REALLY need(mostly want) a faster CS4 workspace without spending the $1600 on another mac license for CS4 (I had it on a PC and it allows 2 computers to use 1 key)
     

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